Fluorescence is a phenomenon in which a substance absorbs light, and almost immediately re-radiates light of a longer wavelength. Fluorescent dyes have been created for use in detecting leaks from fluid containing systems. In use, a fluorescent dye is included in the fluid within the system. A region outside of the system, such as where a leak is suspected, is illuminated with light that has a wavelength that will excite the fluorescent dye. The area being illuminated is inspected for emission from the fluorescent dye. Fluorescent dyes used for this purpose are usually excited by light in the blue to ultraviolet wavelength range, and emit visible light in the green to yellow wavelength range.
Inspection lamps with different wavelength outputs are becoming more popular in many different industrial applications such as leak detection, forensic inspections, and non-destructive testing. Therefore, it is desirable to have one lamp that can provide many different colors of light upon demand. Prior lamps have met this need by using replaceable filters to block undesired colors of light and to transmit only the desired color of light, by using multiple lamp heads each with a different color or colors, by using color wheels, or by using complicated assemblies containing various bulbs or LEDs.